Various arrangements have been proposed and many are in present use today for varying the vertical height of the padded arm rest normally provided on either side of a wheelchair seat. A major problem with all such systems as have been proposed is the difficulty of the wheelchair patient himself or herself to effect the desired vertical adjustment. For example, where telescoping tubes are employed, a small button detent type structure is often utilized to lock the telescoping tubes in selected positions. No difficulty is normally encountered with properly positioning the arm rest at a selected position by a nurse or other attendant. On the other hand, it is often very difficult if not impossible for a wheelchair patient, particularly when use of his or her arms and hands is impaired, to negotiate the necessary action to release the telescoping tubes and thereby permit adjustment of the arm rests.
In U.S. Pat. No. 3,993,351 owned by the same assignee as the present invention, there is disclosed a vertically adjustable wheelchair arm rest wherein an oval shaped collar surrounds the front telescoping tubes and carries a pin projecting into registering openings to lock the tubes in a desired position. This collar presents a fairly large area front surface for engagement by a portion of a patient's body, the patient urging the collar rearwardly to thereby release the pin and permit adjustment of the arm rest.
While the foregoing structure to some extent solves problems associated with adjustable arm rests as described heretofore, for certain types of immobile patients, it is very difficult to move the collar in a rearward direction with the hand or arm of the patient on the same side as the arm rest to be adjusted. While the collar can easily be urged rearwardly by the patient's opposite hand or arm or even wrist stub, it is very difficult for the patient to thereafter move the arm rest with the adjacent arm or hand to a desired vertical position.